There are abundant reserves of heavy oil reservoirs with bottom water, yet production challenges such as premature water channeling often arise during development, leading to high residual oil saturation and water cut. CO2 injection has proven effective in mitigating water breakthrough and enhancing oil recovery. This study investigates the mechanism of CO2-assisted water control and production enhancement in a heavy oil reservoir with bottom water from C Oilfield. Three distinct geological patterns of water channeling were analyzed, and a combined approach of numerical simulation and physical experiments was employed to evaluate the role of CO2 in reservoir performance. The results of study show that water channeling patterns and characteristics vary with reservoir properties, categorized into three types: absence of interlayers, presence of permeable interlayers, and underdeveloped interlayers. In interlayer-free zones, water channeling risk escalates with proximity to the bottom-water zone. Permeable interlayers accelerate water breakthrough timing and severity as their permeability increases. Underdeveloped interlayers exhibit higher water influx and channeling intensity with elevated interlayer flow coefficient. CO2 exists in both gaseous and dissolved phases within the reservoir: gaseous CO2 plays a role of water control by sealing effect. While dissolved CO2 enhances oil production through viscosity reduction and swelling effects. Lower reservoir pressures and higher CO2 injection rates synergistically improve water control effect. This study can provide methodological guidance for analyzing CO2-assisted water control and enhancing production technologies in analogous reservoirs.